Facile Conversion of an Appended Silylamido to a
Silyloxy Ligand via Isocyanate Elimination. Synthesis of
{[(C<sub>5</sub>Me<sub>4</sub>)SiMe<sub>2</sub>O]Zr(η<sup>2</sup>-O<sub>2</sub>CMe)(μ-O<sub>2</sub>CMe)}<sub>2</sub> via the
Carboxylation of [(C<sub>5</sub>Me<sub>4</sub>)SiMe<sub>2</sub>(N-<i>t</i>-Bu)]ZrMe<sub>2</sub>

The reaction of 2 equiv of CO<sub>2</sub> with
[(C<sub>5</sub>Me<sub>4</sub>)SiMe<sub>2</sub>(N-<i>t</i>-Bu)]ZrMe<sub>2</sub> proceeds with
the formation of
{[(C<sub>5</sub>Me<sub>4</sub>)SiMe<sub>2</sub>(N-<i>t</i>-Bu)]Zr(η<sup>2</sup>-O<sub>2</sub>CMe)(μ-O<sub>2</sub>CMe)}<sub>2</sub>
(<b>2</b>),
which reacts with additional CO<sub>2</sub> to afford
{[(C<sub>5</sub>Me<sub>4</sub>)SiMe<sub>2</sub>O]Zr(η<sup>2</sup>-O<sub>2</sub>CMe)(μ-O<sub>2</sub>CMe)}<sub>2</sub>
(<b>3</b>) with the concomitant elimination of OCN-<i>t</i>-Bu. The formation
of
OCN-<i>t</i>-Bu was confirmed by a combination of
GC/MS
and IR measurements; the molecular structures of <b>2</b>
and
<b>3</b> were determined by X-ray crystallography.